Problem: Simplify the following expression: $p = \dfrac{a^2 - 5a - 14}{a + 2} $
Explanation: First factor the polynomial in the numerator. $ a^2 - 5a - 14 = (a + 2)(a - 7) $ So we can rewrite the expression as: $p = \dfrac{(a + 2)(a - 7)}{a + 2} $ We can divide the numerator and denominator by $(a + 2)$ on condition that $a \neq -2$ Therefore $p = a - 7; a \neq -2$